Enhance flows of waxy crude oil in offshore petroleum pipeline: A review

Abstract

In the petroleum industry, the transport of offshore crude oil via pipelines may suffer damage known as wax precipitation. This reduces the flow capacity of the crude oil, reducing its transport efficiency. Under extreme conditions, this may also result in serious damage to equipment. To help alleviate this problem, the petroleum transport and flow characteristics of offshore waxy crude oil in pipelines are investigated, together with the development of several options to help minimize wax precipitation. This paper reviews the current research status for reducing wax precipitation and enhancing crude oil flow in offshore pipelines. Specifically, reducing the viscosity of waxy crude oil, strengthening the process technology of the pipeline and the related flow mechanisms are each investigated. This paper also identifies and discusses areas of study that require further investigation. • Offshore crude oil wax deposition is generated by the precipitation of wax crystals in crude oil. • DRAs, PPD, microbial and hydrate inhibitor decrease the viscosity by reducing the generation of wax crystals. • Skin effect electrical heat tracing increase the temperature of pipeline internal to reduce wax deposition. • Inner wall coating reduces the flow resistance of pipe internal to enhance flows of crude oil. • Hernandez Model, Singh Model and Rygg Model describe the multiphase flow characteristics of crude oil in offshore oil pipelines.